5228-DS08-R datasheet(78/100 Pages) BOARDCOM

78 / 100 page

BCM5228

Data Sheet

7/12/04

Broa d c om Co rp o r a t i o n

Page 66

Auxiliary Status 2 Register (Shadow Register)

Document

5228-DS09-405-R

AUXILIARY STATUS 2 REGISTER (SHADOW REGISTER)

MLT3 Detected. The BCM5228 returns a 1 in this bit whenever MLT3 signaling is detected.

Cable Length 100X [2:0]. The BCM5228 provides the cable length for each port when a 100TX link is established.

ADC Peak Amplitude [5:0]. The BCM5228 returns the A to D converter’s 6-bit peak amplitude seen during this link.

APD Enable. When in normal mode, if this bit is set to a 1, the BCM5228 enters auto power-down mode. If this bit is set and

the link is lost, the BCM5228 enters low power-down mode. When energy is detected, the device enters full power mode.

Otherwise, it wakes up after either 2.5 seconds or 5.0 seconds, as determined by the APD Sleep Timer bit. When the

BCM5228 wakes up, it sends link pulses and also monitors energy. If the link partner’s energy is detected, the BCM5228

device continues to stay in wake-up mode for a duration determined by the APD wake-up timer before going to low power

mode.

APD Sleep Timer. This bit determines how long the BCM5228 stays in low power mode before waking up. If this bit is a 0,

the BCM5228 device waits approximately 2.5 seconds before waking up. Otherwise, it wakes up after approximately 5.0

seconds.

Table 43: Auxiliary Status 2 Register (Shadow Register 27d, 1Bh)

BIt

Name

R/W

Description

Default

MLT3 Detected

R/O

1 = MLT3 detected

14:12

Cable Length 100X[2:0]

R/O

The BCM5228 shows the cable length in 20-meter

increments, as shown in Table 44.

000

11:6

ADC Peak Amplitude[5:0]

R/O

A to D peak amplitude seen

00h

APD Enable

R/W

0 = Normal mode

1 = Enable auto power-down mode

APD Sleep Timer

R/W

0 = 2.5-second sleep before wake up

1= 5.0-second sleep before wake up

3:0

APD Wake-Up Timer[3:0]

R/W

Duration of wake up

0001

Note: R/W = Read/Write, RO = Read Only, SC = Self Clear, LL = Latched Low, LH = Latched High, LL and LH Clear

after read operation. MII Shadow register bank 1 is accessed by setting MII register 1Fh bit 7 to a 1.

Table 44: Cable Length

Cable Length 100x [2:0]

Cable Length in Meters

000

< 20

001

20 to <40

010

40 to <60

011

60 to < 80

100

80 to < 100

101

100 to < 120

110

120 to < 140

111

> 140

5228-DS08-R 数据表(PDF) 78 Page - Broadcom Corporation.

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